The present invention relates generally to a metallic hollow golf club head, and specifically, to the placement of a stamped insert into the face of the club. This invention is also directed to a weight element being located on the sole in the heel/skirt regions of the club.
Golf club xe2x80x9cmetal woodsxe2x80x9d, were originally manufactured primarily by casting of durable metals such as stainless steel, aluminum, beryllium copper, etc. into a unitary structure comprising of a metal body, face and hosel. As technology progressed it became more desirable to strengthen the face of the club, and usually this was achieved by using a titanium material.
With a high percentage of amateur golfers constantly searching for more distance on their drives, the golf industry has responded by providing golf clubs specifically designed with distance in mind. The head sizes have increased which allows for the club to possess a higher moment of inertia, which translates to a greater ability to resist twisting on off-center hits. As a wood head becomes larger, its center of gravity will be moved back away from the face resulting in hits flying higher than expected. Reducing the lofts of the larger head clubs can compensate for this. Also the larger heads, because the center of gravity is moved further away from hosel axis, can cause these clubs to remain open on contact, thereby inducing a xe2x80x9cslicexe2x80x9d effect (in the case of a right-handed golfer the ball deviates to the right). Offsetting the head and incorporating a hook face angle can help compensate for this by xe2x80x9csquaringxe2x80x9d the face at impact, but often more is required to eliminate the xe2x80x9cslicexe2x80x9d tendency. The present invention provides such a solution.
Another technological breakthrough in recent years towards providing the average golfer with more distance is to make larger head clubs, while keeping the weight constant or even lighter, by casting consistently thinner shell thickness and going to lighter materials such as titanium. Also the face of the clubs have been steadily becoming extremely thin. The thinner face will maximize what is known as the COR (Coefficient of Restitution). The more a face rebounds upon impact, the more energy that may be imparted to the ball, thereby increasing distance.
In order to make the faces thinner, manufacturers have moved to a forged or stamped metal face which are stronger than cast faces. Common practice is to attach the forged or stamped metal face by welding them to the body at the sole and crown junctions. The present invention provides a novel method for attaching an impact face to the club without sacrificing any COR (Coefficient of Restitution) value in the club.
The prior art teaches methods to enhance the weight distribution of metal woods to help reduce the club from being open on contact with the ball. Usually, this is accomplished by the addition of weights to the body casting itself or strategically adding a weight element at some point in the club. Many efforts have been made to incorporate weight elements into the metal wood head. They are usually placed at specific locations, which will have a positive influence on the flight of the ball or to overcome a particular golfer""s shortcomings. As previously stated, a major problem area of the higher handicap golfer is the tendency to xe2x80x9cslicexe2x80x9d which besides deviating the ball to the right, also imparts a greater spin to the ball. To reduce this tendency, the present patent teaches the placing of a weight element directly into the club head. The placement of the weight is designed so that the spin of the ball will be reduced, and also a xe2x80x9cdrawxe2x80x9d (a right to left ball flight for a right-handed golfer) will be facilitated into the ball flight. This ball flight pattern is also designed to help the distance challenged golfer because a lower spinning ball will generally roll a greater distance after hitting the ground than it would roll with a higher spin. The present invention provides such a golf club.
Several patents have been issued which are directed towards using an insert in the face of the club to increase the strength therein. One such patent, U.S. Pat. No. 5,344,140 issued to Anderson, cites a face plate of forged metal.
None of the above inventions and patents, either singly or in combination, is seen to describe the instant invention as claimed.
In accordance with one aspect of the invention, a metal wood golf club head is provided which includes a hollow body having a stamped metal impact face welded to it. The body is preferably cast as a single member and includes an inner cavity surrounded by a sole plate, a crown portion, a toe portion, a heel portion, a skirt portion and a face perimeter forming an oval opening. The present invention utilizes a sheet metal insert that is preferably placed into the face approximately 0.20xe2x80x3 removed from the crown portion and 0.20xe2x80x3 removed from the sole plate. The face insert should be at least 0.15xe2x80x3 from either the crown portion or the sole plate. The shell of the face perimeter is preferably of uniform thickness and less than the thickness of the insert. The insert preferably has a thickness that varies based on a double radii method that is described later.
In accordance with another aspect of the invention, the club head includes the addition of a weight element to the sole plate. The purpose of this weight addition is to reduce the tendency of a golfer to slice and to lower the spin rate of the ball, which actually tends to increase distance. The weight element is centered substantially on a projection extending away from and generally perpendicular to the impact face on a line through a point where the shaft centerline would meet the sole plate. The center of gravity of the weight element is thus substantially directly behind the point where the hosel axis intersects the sole plate. Preferably, the weight element is placed at a juncture of the heel/skirt portions of the sole plate. The weight element may be either cast with the body or can be a separate piece attached to the sole plate by conventional means such as welding. The center of the weight element should be at least 1.0xe2x80x3 and preferably more than 1.5xe2x80x3 from the intersection point of the hosel centerline and the sole plate. It is anticipated that the weight element be greater than 12 grams and more preferably greater than 16 grams.